Japanese Patent Application Publication No. 2013-253512 discloses an internal combustion engine (hereinafter, referred to as “variable compression ratio internal combustion engine) including a variable compression ratio mechanism arranged to vary an engine compression ratio in accordance with a rotation position of a first control shaft. A link mechanism is provided between an actuator such as a motor which is arranged to drive the first control shaft, and the first control shaft. A second control shaft is provided to this link mechanism. The second control shaft is connected through a lever to the first control shaft. The second control shaft is supported within a housing fixed, for example, to an engine main body.
In this variable compression ratio internal combustion engine, the large load in the axis inclining direction is acted to the bearing portion of the first link pin connected to the first arm portion of the first control shaft in which the bending/torsion vibration is generated. Accordingly, the first link pin is strongly contacted at the one end portion of the bearing portion. That is, the load of the partial contact tends to be large. On the other hand, on the second link pin's side, the first link pin and the lever are disposed between the first control shaft and the second link pin. Accordingly, the load is decreased by the clearance of the bearing portion between the first link pin and the lever. The load in the axis inclining direction to the bearing portion is suppressed to the low value relative to the first link pin. Consequently, the local surface pressure acted to the bearing portion is low.
Therefore, when the identical load is acted to the first link pin and the second link pin, the local surface pressure of the first link pin is increased, so that the abrasion is easy to be progressed.